This invention relates generally to a process for producing beer of low original gravity. More particularly, the invention relates to a process for producing beer of low original gravity without special elevation of the degree of attenuation.
In recent years, there has been a widespread popularization of brewed beverages called light beers, particularly in the United States of America. A light beer is characterized, in general, by a flavor which is lighter or fresher than that of a beer of an original gravity of wort of 10 to 12 degrees Plato (.degree.P) (hereinafter referred to as "regular beer"), and its original gravity of wort is set lower than that of a regular beer in many cases. Since the calorific value of a beer may be considered to be determined by the original gravity of wort, although it increases or decreases somewhat depending on the degree of attenuation of the beer, a light beer of this character is, at the same time, a low-calorie beer whose calorific value is less than that of a regular beer.
In the prior art, the known processes for brewing beer of low original gravity of this character are broadly classified as follows:
(1) Those in which worts of gravities of 6 to 9 .degree.P are fermented. PA1 (2) Those in which saccharifying enzymes are used. PA1 (3) Those in which fermentable sugars are used. PA1 (4) Those in which dextrin assimilable yeasts are used. PA1 (5) High-gravity brewing PA1 (6) Adjunct fermentation process. PA1 (7) Kraeusening process. PA1 (8) Blending of worts (Darauflassen process). PA1 mixing a high-gravity liquor comprising a fermenting wort of an original gravity of 14 to 21 degrees of plato which has passed through the high kraeusen period and a low-gravity liquor comprising a fermenting wort or wort of an original gravity of 3 to 6 degrees of plato and PA1 subjecting the resulting mixture to fermentation thereby to obtain a beer of an original gravity of 6 to 9 degrees of Plato.
Of these processes, process (1) does not differ from the traditional brewing process except for the use of a lower original gravity of wort, and a beer of low original gravity of a degree of attenuation not varying from that of a regular beer is brewed by this process. In process (2), amyloglucosidase, for example, is added to the wort at the time of fermentation thereby to convert the dextrin of the wort into sugars which brewers' yeast can assimilate. By this process (2), a beer of low original gravity of a degree of attenuation higher than that of a regular beer is brewed. Since the fermentable sugar content of the wort in process (3) is high, and also because even dextrin not assimilated by ordinary brewers' yeast is also assimilated in process (4), beers of low original gravity of degrees of attenuations higher than that of a regular beer are brewed by these processes.
In addition to these processes for brewing beers of low original gravity, the following processes wherein beers of low original gravity are obtained by diluting regular beers or beers of higher original gravities than regular beer are also possible.
This high-gravity brewing (5) is a process in which a wort for providing a beer of an original gravity higher than that of the desired beer to be produced is fermented, and thereafter the resulting beer is diluted with water to obtain the beer of the desired original gravity, as described in the BREWERS DIGEST, Vol. 51, p. 34 (1976). This technique appears to be spreading in the U.S.A. as a process for producing regular beer, probably because of its economical feature, and it is reported that, among the processes for producing beer of low original gravity in the U.S.A., there is a process in which, by diluting the beer of high original gravity with water, beer of an original gravity of 6 to 9 .degree.P is obtained.
Furthermore, the following processes are known as techniques wherein two kinds of worts or beers are mixed.
The adjunct fermentation process (6) is a technique in which a sugar solution prepared from an adjunct is caused by a yeast to ferment thereby to form an alcohol solution, which is mixed with an all-malt beer thereby to obtain a beer of a desired original gravity of wort. Reference is made to MBAA TECHNICAL QUARTERLY, Vol. 13, p. 22 (1976).
In addition to these processes, there is a process disclosed in Japanese Patent Laid Open Publn. No. 54591/1974, which also should perhaps fall within the category of an adjunct fermentation process since it relates to the proposal of the proposer of the adjunct fermentation process.
The kraeusening process (7) is a technique for promoting secondary fermentation by replenishing yeast having vitality. The darauflassen process (8) is also a common technique used for purposes such as promotion of the primary fermentation and homogenization of the fermenting wort.
Another common technique is the procedure of blending in which worts or beer produced from the same process are mixed for the purpose of homogenization.
While a great number of various processes relating to the production of beer of low original gravity have been proposed or suggested in this manner, none have been completely satisfactory to the best of our knowledge and belief. The principal difficulties and problems accompanying these processes in the prior art are as follows.
In the first place, the product called light beer is not a beer developed in order to establish a new kind of beverage but is one intended to be a low-calorie beer to which a lightness or freshness has been imparted without spoiling the flavor of regular beer. Beers of low original gravity which we experimentally produced in accordance with these known techniques, however, had flavors which were inferior to those of regular beers.
In general, organoleptic appeal to consumers of a food or a beverage depends on complicated factors. Furthermore, it is impossible to quantitatively express the appeal as a contribution of each of and as an aggregate of whole of these various factors, whereby evaluation of the appeal must unavoidably be determined on sensory or taste tests. In addition, it is frequently observed that the appeal as a whole varies as a result of a variation in only a certain single factor, and, moreover, it is impossible to predict how a variation in a certain factor will affect the appeal as a whole.
This uniqueness of organoleptic appeal of a food or a beverage was observed also during taste tests on beer of low original gravity which we experimentally produced. That is, as a result of introducing variations in the processes for producing regular beer as described hereinbefore, it was indicated that in each beer of low original gravity, "body" was deficient, and the flavor was poor, the organoleptic appeal being markedly inferior to that for a regular beer.
More specifically, while process (1) is a most fundamental process in that it is for brewing a beer low original gravity, merely using a wort of low gravity will result in a beer which is of disappointing flavor and cannot be said to be comparable to regular beer. In processes (2) and (3), as a result of the raising of the degree of attenuation by the use of a saccharifying enzyme and a fermentable sugar, the formation of aroma components such as ethanol, higher alcohols, and esters is promoted, whereby an augmentation of the bouquet or flavor of the resulting beer of low original gravity can be expected. However, we have found that, while beers of low original gravity obtained by these processes possess a remarkable characteristic resulting from higher degree of attenuation than those of regular beers, they have not been developed to a level where, as a result of the reinforcement of their bouquet or flavor, the inadequacy of their flavor has been amply made up for. In the case of process (2), furthermore, it is said that since the saccharifying enzyme is not inactivated by an ordinary heat treatment after bottling, it sometimes causes a deterioration of the bouquet or flavor of the resulting bottled beer.
In the case of process (4), we have found that the beer obtained thereby with the use of Saccharomyces diastaticus as a dextrin assimilable yeast possesses a bouquet or flavor different from that of a beer brewed with an ordinary brewers' yeast and is a beverage of markedly inferior organoleptic appeal and characteristics not found in beer.
In comparison with these processes which start with low-gravity worts, process (5), in which a wort for producing a beer of an original gravity higher than that of the desired beer to be produced is fermented and is thereafter diluted with water to obtain a beer of a specific original gravity appears to be a promising process for producing a beer of low original gravity of excellent flavor. The reason for this is that, since a large quantity of esters are formed in the fermenting wort (or wort fermented) of high-gravity wort according to this process, it can be expected that the drawbacks possessed by beer obtained by fermenting a low-gravity wort directly as it is will be compensated for.
However, when we experimentally produced a beer of low original gravity by fermenting a wort with a high original gravity of 15 .degree.P or higher than thereafter diluting the fermented wort with water to a specific original gravity of wort, this beer, while exhibiting estery flavor imparted thereto, was found to cause the drinker to strongly taste the energy flavor, and was found to be a beer which had lost its flavor balance.